It has been known for many years that the fuel supplied to an internal combustion engine is not completely consumed in the operation of the engine. A substantial percentage of the fuel is carried completely through the engine and exits from the exhaust system. This unused fuel not only wastes the money of the operator of the motor vehicle but also adds to the air pollution problem.
The federal government and many states have passed laws substantially restricting the emissions from the exhaust system of an internal combustion engine. In order to comply with these federal and state requirements, the internal combustion engine used in motor vehicles have been adjusted to burn a very lean mixture of fuel and air. While this reduces the amount of fuel used in the engine, and in turn the amount carried through the engine, it also has the effect of providing a cooler combustion mixture. The low amount of fuel used in each charge to the cylinder of the engine causes the engine to tend to misfire and to not properly burn all of the fuel. There are insufficient fuel particles to carry the flame front throughout the cylinder to consume all of the fuel particles contained therein. The remaining fuel passes out through the exhaust system where catalytic means are used to consume the fuel to reduce the noxious emission products produced in the operation of the engine.
Since the amount of fuel contained in each charge to the cylinder is reduced, the natural consequence is that the amount of energy produced by each firing of the cylinder containing the lean fuel/air mixture is also reduced. The overall output, then, of the engine is diminished due to the consequences of adjusting the engine to use less fuel per cylinder charge. If something could be done to improve the percentage of fuel consumed in each cylinder charge, the output energy from the engine would be increased and the amount of unused fuel passing through the engine would be substantially reduced. The desirable outcome would be improved engine performance and reduced air pollution.
Many attempts have been made to improve the operation of internal combustion engines by applying energy of some form to the fuel or fuel/air mixture. For example, U.S. Pat. No. 3,940,407 applies pulses of electrical energy to the air input stream to the engine to generate ions which are then mixed with the fuel for the engine. The ions are alleged to increase the performance of the engine. U.S. Pat. No. 3,976,726 applies pulsed energy to the liquid fuel stream entering the carburetor at the resonant frequency of the molecular components of the fuel to activate the fuel and in turn, enhance the performance of the engine. U.S. Pat. No. 4,138,980 applies RF energy to the combustible plasma air/fuel mixture in the combustion chamber to excite at least one resonant mode to enhance preconditioning and combustion of the fuel in the engine. U.S. Pat. No. 4,401,089 employs an ultrasonic transducer in the engine manifold to vaporize the fuel prior to entry of the fuel/air mixture into the cylinders. U.S. Pat. No. 4,556,020 employs an ultraviolet lamp in the combustion chamber which dissociates oxygen molecules in the flame front to stimulate combustion of the flame to allow the burning of lean fuel/air mixtures.
Of particular interest to the present invention is U.S. Pat. No. 4,338,905 which employs a vaporization chamber using resistive heating and an ultrasonic transducer to vaporize fuel. The vaporized fuel is then fed to the PCV input to the carburetor where the vaporized fuel is added to the conventional carbureted fuel/air mixture to increase the efficiency of operation of the engine.